This invention relates to a communication network management system and, more particularly, to a communication network management system for managing and operating a network in accordance with a business policy or user policy.
Communication networks employ a variety of network technologies, e.g., SDH, ATM, FR, WDM and IP. In addition, communication networks are becoming increasingly more complicated in form and are divided into a wide variety of domains (subnetworks) as in the manner of access networks, backbone networks, SDH (Synchronous Digital Hierarchy) networks and WDM (Wavelength Division Multiplexing) networks. These domains are managed by an EMS (Element Management System) and these are in turn managed by an NMS (Network Management System). The NMS and EMS both have a manager/agent architecture defined by the ISO. The NMS transmits an operating command to a manager agent within the EMS using a prescribed management protocol, e.g. the CMIP (Common Management Information Protocol), and the status of a domain is acquired by the EMS to thereby manage the overall network.
FIG. 16 is a diagram useful in describing a system management model and illustrates the relationship between a manager/agent architecture and the CMIP and managed objects (MO). A manager M operates managed objects MO, which are managed by an MIB (Management Information Base) within an agent A.
More specifically, the managed objects MO are obtained by using an object-oriented technique to model a network resource such as a line, switch, multiplexer and virtual communication path in the domain to be managed. A variety of status variables possessed by the network resource are referred to as the attributes possessed by the managed objects MO. Network management is for operating these managed objects MO. Operations include the following:                (1) creation of a managed object MO (M-CREATE);        (2) deletion of a managed object MO (M-DELETE);        (3) reading of an attribute of a managed object MO (attribute acquisition) (M-GET);        (4) setting or changing of an attribute of a managed object MO (M-SET);        (5) implementation of a function possessed by the managed object MO (M-ACTION); and        (6) receiving an event report from a managed object MO (M-EVENT-REPORT).        
Though the manager M is a mechanism which plays the main role in network management, it does not directly operate a managed object MO; it is an agent A that operates the managed objects MO. For this reason, the manager M uses the management protocol CMIP to send an operating command to the agent A, thereby operating the network indirectly to implement management. It is possible with this management operation to adopt a plurality of managed objects MO as objects of control simultaneously by a single management operation.
FIG. 17 is an explanatory view illustrating the concept of a basic network hierarchy in network management. In accordance with a TMN (Telecommunication Management Network) defined by the ITU-TM.3000 series, network management functions are classified into the following four layers and the roles thereof are clarified:                (1) element management layer EML;        (2) network management layer NML;        (3) service management layer SML; and        (4) business management layer BML (not shown).        
Element management systems (EMS) 11, 12 are each connected to one or more network elements (NE) 1˜4 within corresponding domains and control the managed objects MO to manage the network elements NE and the domains (subnetworks SN) constituted by the network elements. A network management system (NMS) 21 is connected to one or a plurality of element management systems (EMS) 11, 12 and manages the network elements of the overall network via these element management systems.
A service management system (SMS) 31 is connected to the network management system (NMS) 21 and, in accordance with a command from a user interface (user terminal) 32, requests the network management system (NMS) 21 for prescribed network information, receives this network information and outputs the same. Further, a user terminal 22 requests the network management system (NMS) 21 directly for prescribed network information, receives this information and displays the information on a display unit or prints out the information using a printer.
FIG. 18 illustrates an example of the configuration of a communication network. Here a plurality of element management systems EMS are provided for corresponding ones of domains (subnetworks SN1˜SN4). A network management system NMS is connected to each of the element management systems EMS and manages the network via these element management systems EMS. The subnetworks SN1, SN4 are access networks implemented in the ATM (Asynchronous Transfer Mode), the subnetwork SN3 is a core network implemented by SDH, and the subnetwork SN2 is a core network (SDH) implemented by WDM. IP connection points IPC1, IPC2 are points of connection to an IP network (not shown), which is a business network.
FIG. 19 is a diagram useful in describing the relationship among systems. This diagram illustrates the relationship among the systems of FIG. 17 taking into consideration the manager/agent architecture shown in FIG. 16. Here M represents a manager, A an agent, MO a managed object, APL an application and MIB a management information base. The higher and lower layers have a manager M—agent A relationship, and communication is performed via the management protocol CMIP.
The network management system (NMS) 21 stores the managed object MO, which is for managing network information that connects the domains, in the management information base MIB and functions as the agent A, which supplies network information to the service management system (SMS) 31. Further, the network management system (NMS) 21 behaves as the manager M with respect to the element management systems (EMS) 11, 12 and implements network management by operating the managed object MO, which has been stored in the management information base MIB, via the agent function of the element management systems (EMS) 11, 12. Further, through use of the user interface function, the network management system (NMS) 21 makes it possible to command the manipulation of network information.
The element management systems (EMS) 11, 12 store the managed objects MO for managing the domains in the management information bases MIB and function as agents A for supplying network information to the network management system (NMS) 21 of the higher layer. Further, the element management systems (EMS) 11, 12 behave as the managers M with respect to the network elements (NE) 1, 2, and perform network management within a specified range by operating the managed objects MO, which have been stored in the management information bases MIB, via the agent functions of the network elements 1, 2, . . .
In order to exploit network resources effectively, there is now need for a system which can implement network management in accordance with a business network operations policy. Conventionally, public networks which provide leased lines to businesses furnish network services of uniform high reliability and quality in compliance with the wishes of users. Recently, however, there has been growing demand for a network service which, in accordance with business policy, makes it possible to designate the quality of a public network, or to change the quality thereof dynamically, in conformity with the network quality desired by individual users. To satisfy this demand, a service has been made available in which a Service Level Agreement (SLA) is concluded between a public network and a user and the public network adjusts the user network quality on the basis of the SLA.
Practical public networks are implemented using various network technologies adapted to the traffic characteristics of users, namely network technologies such as IP, FR (Frame Relay), SDH and ATM (see FIG. 18). In such networks, it becomes necessary to change the SLA dynamically if user traffic changes or increases in an IP network, by way of example. In accordance with the agreement with the user, therefore, it is necessary to convert the SLA information to the parameters of the network (IP, FR, SDH, ATM, etc.) being used in the public network.
Communication traffic through a plurality of domains (subnetworks) is dependent upon the QoS (Quality of Service) of the traversed domains. For this reason, there are cases where QoS requirements cannot be satisfied fully depending upon applications where quality is important, such as TV conference and voice applications, real-time applications, etc. In order to satisfy QoS requirements using these applications, it is necessary to request end-to-end quality, select end-to-end domains (subnetworks) that can provide the demanded quality assurance and carry out QoS policy provisioning. Here “provisioning” means establishing paths and networks. With QoS policy provisioning, it is necessary to convert SLA information, e.g., maximum and minimum end-to-end speeds required by the user, to parameters (cell rate in case of ATM and containers in case of SDH) conforming to the network technology (IP, FR, SDH, ATM, etc.).
With regard to SLA heretofore, general agreements such as guarantees of usable time (availability) have already been introduced. However, it is required that parameters dependent upon a specific network technology such as IP, FR, SDH or ATM be set in a data format that is dependent upon the network technology by the information system administrator of the business. It is necessary, therefore, to have an understanding of the networks on both the company and public-network sides. This means that one must have the know-how to deduce specific parameters conforming to the network from the abstract requirements of the user, and hence obstacles are confronted when making changes dynamically. For example, deducing the parameters of the network takes time. In addition, management of a public network also requires a maintenance man who knows how to ascertain the actual status of the network.